1. Ensure your chosen UPnP server software can serve the file type you are trying to access
2. Make sure the files are non-DRM
AXN/MXN can only play non-DRM files. Files that have DRM controls cannot be played by AXN/MXN. Some servers may be able to authorize and de-crypt Microsoft Playsforsure before then serving the content to the AXN/MXN but this operation is not guaranteed as it is purely a function of the server.
3. If attempting to play 24-bit WAV or FLAC content note a wired Ethernet connection is normally required for reliable operation due to bandwidth considerations
4. Check that the AXN/MXN can play back the file type you are trying to access
WMA, AAC, MP3, Vorbis, FLAC and WAV can currently be played. The AXN/MXN does not support ALAC, WMA Pro, WMA lossless, RAW, AU or other file types not mentioned.